Pulmonary and Anti-allergy Drugs

There are two broad categories of allergic reaction: immediate and delayed hypersensitivity. Delayed responses include allergies to poison ivy, drugs, chemicals, etc., while immediate hypersensitivity includes syndromes such as allergicrhinitis, uticaria, and asthma. Bronchial asthma may be classified into intrinsic (not clearly associated with a known imunologic mechanism) and extrinsic or allergic asthma that may be mediated by the union of antigen with specialized immunoglobulins (IgE). Theories concerning the pathogenesis of extrinsic asthma have been advanced, including decreased β-adrenoreceptor activity, “increased α-adrenergic activity” and changes in reflex cholinergic mechanisms. The pathogenesis may be divided into six categories. Experiments on rat and guinea pig include use of Beta-Adrenoreceptor Stimulants, α-Adrenoreceptor Antagonists, Anti-cholinergics, Prostaglandins, Corticosteroids, Phosphodiesterase Inhibitors, and peptides. Phannacokinetics of dihydroxypropyl theophylline (dyphylline) by intramuscular and by oral administration (10 mg/kg) indicate a half-life of two hours and ready absorption independent of route. A combination of theophylline—ephedrine has been shown to be no more effective than theophylline alone and also to cue GII side, insomnia and restlessness not found with the same dose of the individual drugs.